Home >Online Product Documentation >Table of Contents >Specifying That an Element Can Contain One or More Elements in DTDs
Often, you want an element to contain a sequence of elements. Some of these elements might be required, some might be optional, and some might be able to occur more than once. There might even be a group of elements in which only one can appear.
At this point, you can add
The procedure is the same for these modifiers. The only difference is the modifier you select. For example, following are the instructions for adding optional elements:
In an instance document, the contained elements must appear in the order in which they are specified in the DTD.
To move a required element that can appear only once, click its name and then use the up and down arrows.
Alternative: Right-click the item you want to move. Select Move Up or Move Down from the shortcut menu.